In operation of a piston pump, an inlet control valve (ICV) opens a fuel inlet in the working volume during an intake stroke and resists a fuel back flow during a pump stroke. Accordingly, to achieve optimized flow efficiency the valve should open at the very beginning of the intake stroke and close at the end of the intake stroke (e.g., at the beginning of pumping stroke).
Some existing ICVs are designed to open at a predetermined pressure, sometimes referred to as a valve opening pressure (VOP), which is achieved by a spring that provides a defined amount of force. Thus, the opening of the valve is not directly dependent on valve movement (i.e., position), but rather on a fluid pressure in a pump element. Furthermore, these valves are designed to close when the pump stroke begins. In some prior designs, the closing of the valve is again driven by the pressure conditions in the pump element. Such techniques for controlling an ICV operation can lead to a number of unwanted problems, such as reduction in volumetric pump efficiency, slow ICV response, fluid cavitation (for example, due to slow response and/or backflow), and mechanical damage (e.g., caused by cavitation, valve bounce).